grovemiller



Jan. 3 1956 D, A. GROVEMILLER LAMP BASE Filed July 1, 1954 Inven hor DaLe A. GrovemiLLer b5 4% 2 His LAMP BASE Dale A. Grovemiller, Euclid, Ohio, assignor to General Electric Company, a corporation of New York Application July 1, 1954, Serial No. 440,780

5 Claims. (Cl. 339-445) The present invention relates to bases for electric lamps and similar devices, and particularly for double-ended elect ric discharge lamps of the type having preheatable electrodes mounted at the ends of a tubular glass envelope with a pair of spaced apart current inlead wires for each of the electrodes extending from the ends of the envelope.

In the copending Lemmers application, Serial No. 380,279, filed September 15, 1953, and assigned to the assignee of the present application, two species of diskshaped bases useful for lamps of the above type are disclosed and claimed. The bases of the aforesaid copending application make possible the use of the current inlead wires at each end of the tubular lamp as the lamp terminals or contacts, thus dispensing with the usual outwardly projecting contact pins.

Thebases include a disk-shaped member of electrically insulating material in which the lamp inleads are re cessed for safety purposes. An inlead receiving passage extends through the disk and a recessed portion of an exposed outer face of the disk includes a slot or groove which communicates with said passage and extends transversely of the passage. An inlead is threaded through the passage and is bent over into and anchored in the groove. The wallsof the passage are spaced apart a suilicient distance to accommodate therebetween an inlead of the lamp and an inserted electrical contact of a lamp holder and are shaped to support the accommodated inlead in position for electrical engagement with the accommodated contact. The groove in the body member is substantially deeper than the diameter of the accommodated inlead wire to protect the part thereof in the groove from accidental contacts. The openings of the passage and the groove at the surface of the member are too small for the inlead therein to be touched accidentally in ordinary handling of the lamp. This is an important safety feature of such bases.

Inone species of the base a separate passage is provided for each of the inleads. In the other species, how'- ever, a 'single passage is provided through the center of theinsulating disk member and the passage is of sutlicient size to accommodate both inlead wires and two holder contacts, one for each of the said inleads.

In the latter species of the base a pair of aligned grooves extend in opposite directions from opposite sides of the single passage and the bottoms of the grooves are provided with narrow recesses into which the end portions of the inleads are forced to anchor the inleads in the insulating member. The inleads terminate in cavities provided in the disk at the outer ends of the grooves and additional anchoring means, such as pins forced into the cavities, may be provided for the inleads.

In mounting the latter species of base on the end of the lamp envelope, the center of the disk should coincide with the longitudinal axis of the lamp envelope, and the aligned grooves, in which the end portions of the inleads are anchored, should lie in the plane including the 2,733,421 Patented Jan. 31, 1956 spaced points at which the inleads emerge from the ends of the lamp envelope. This would assure proper parallel positioning of the portions of the inleads extending along the passage and lying against opposite sides of the passage for engagement with the inserted lamp holder contacts. As a practical matter, however, such rotational orientation of the base with respect to the end of the envelope is diflicult of accomplishment in the manufacture of the lamp and, if attempted, would add considerably to the complexities and the cost of manufacture of the lamp.

The principal object of the present invention is to provide a lamp base of the above type having a single central passage for accommodating the inleads at one end of the lamp envelope and of such'structure that the inleads are in parallel positions in the passage regardless of the rota tional position of the disk-shaped base with respect to the end of the tubular envelope. Another object of the invention is to provide such a base of simple structure, capable of manufacture and assembly with the lamp on high-speed machines. A further object of the invention is to provide a lamp equipped with such bases. Further objects and advantages of the invention will appear from the following detailed description of a species thereof, from the drawing and from the appended claims.

A feature of the invention is a base of the above type including a guide slot integral with the disk and consti tuting the only opening at the inner end of the passage for directing the inleads into parallel positions longitudinally of the passage while the inleads are being thread ed through the passage and the ends thereof anchored in the insulating disk. The parts of the disk defining the guide slot are integral molded parts of the plastic insulating disk. and the ends of the guide slot are shaped'to provide support against lateral displacements of the anchored inleads in the passage.

' In the drawing accompanying and forming part of this specification, an embodiment of the invention is shown in which:

Fig. l is a side elevational view of a double-ended elec tric discharge'lamp provided with bases embodying the invention;

Fig. 2 is a sectional view of one end of the based lamp shown in Fig. 1, and Figs. 2a and 2b are, respectively, a front and back view of the base in one of the angular positions with respect to the tubular lamp envelope which may be assumed thereby when mounting the base on the envelope end;

Figs. 3, 3a and 3b are similar to Figs. 2, 2a and 2b, showing the base in another angular position which may be assumed thereby in mounting the base on the envelope; e Fig. 4 is a sectional perspective view of the base taken along the line 4-4 of Fig. 3a, with the inleads of the lamp shown in the position assumed thereby when the'base is in the angular position with respect to the end of the envelope shown in Fig. 3, and

Fig. 5 is a similar view of the base taken along the line 5-5 of Fig. 2b and in the reversed position from that shown in Fig. 4 and with the inleads in the position shown in Fig. 2.

Referring to Fig. 1 of the drawing, in which like numbers denote like parts in all the figures, the doubleended, electric discharge lamp comprises a tubular glass envelope 1 provided with bases 2 and 3 attached to its ends. The bases 2 and 3 are of identical structure and the internal parts of only the base 3 have been shown in Figs. 2 to 5 for conciseness in description.

The base 3 comprises an annular metal shell 4, which is suitably made of sheet aluminum, and a disk 5 of electrically insulating material, such as an organic plastic. The disc 5 may be made of commercial plastic molding compounds, such as those comprising phenol-furfural resins or phenolic resins. The inner rim of the shell 4 is embedded in the periphery of the insulating disk to mechanically join these base members, as shown in Figs. 2 to 5. The base 3' is secured to the end of the glass envelope 1 by a body of basing cement 6.

The disk 5 has a raised elongated embossment 7 extending across its center and projecting outwardly from the base for engaging holders (not shown) for the lamp. A hexagonal passage 8, slightly flattened so as to be elongated in cross section, is provided in the embossed portion 7 of the disk 5. The metal wire' current inleads 9 and 10 connected to the ends of the electrode 11 and extending through the press 12 of the stem 13 of; the glass envelope 1 extend through the passage 8 in the disk 5 of the base 3 and constitute electrical terminals for the lam The outer face of the embossment 7 is recessed to define two cavities 14 and 15 spaced from the central passage 8. The cavities 14 and 15 are connected to the passage 8 by the short grooves 16 and 17. Also, the outer face of the embossment 7 is slotted or notched between the cavities 14 and 15 and its ends, as shown at 18 and 19 in Figs. 2 to 5, so that the outer ends of inlead wires 9 and 10 threaded through the passage 8 may be bent in opposite directions and laid into the grooves 16 and 17, across the cavities 14 and 15 and extend through the slots 18 and 19 and beyond the rounded ends of the embossment 7, as shown in broken lines in Fig. 2. This arrangement of these base portions facilitates the anchoring of the inleads 9 and 10 in the disk 5, as disclosed and claimed in the copending Marz application, Serial No. 440,777, of even date herewith, and assigned to the assignee of the present application.

In accordance with the disclosure of the Marz application, after the inleads 9 and 10 have been so positioned on the disk 5, the portions thereof extending beyond the rounded ends of the embossment 7 are cut ofi flush with the said ends of the embossment and the parts of the inleads overlying the cavities 14 and 15 are crimped into the cavities to anchor the said portions, as shown in full lines in Fig. 2.

The depth of the grooves 16 and 17 and the cavities 14 and 15 is made greater than the diameter of the inlead wires 9 and 10, and the width of the passage 8 and that of grooves 16 and 17 and notches 18 and 19 is made so narrow that accidental contacts with the said inleads cannot occur in handling the lamp incident to its mounting or dismounting the electrical fixtures. This is .an important safety feature of the base structure.

When the base 3 is mounted on the lamp envelope 1 in the position shown in Fig. 2, that is, with the cavities 14 and 15 in a plane including the points at which the inleads 9 and 10 emerge from the press 12 of the envelope, the inleads 9 and 10 anchored in the cavities 14 and 15 extend in spaced parallel position through the flattened hexagonal passage 8 and along the vertices of the convergent end walls 20, 21 and 22, 23, respectively, of the passage 8 (Fig. 2a). The inleads 9 and 10 are thus supported by the said end walls of the passage 8 against lateral displacements and are properly positioned within the base 3 for making a pressure contact within the passage 8 with the inserted contacts of a'lamp holder as described above.

In mounting the base 3 on the end of the lamp envelope 1, especially by automatic machines, the base 3 may and usually does assume a different rotational position with respect to the envelope end than that shown in Figs. 2, 2a and 2b. The most extreme angular displacement possible of the base from the position thereof shown in Fig. 2 is 90 degrees. In Figs. 3, 3a and 3b of the drawing the base is shown in this extreme angularly displaced position.

When the base 3 is in such angularly displaced posi: tions as that shown in Fig. 3, unless means is provided to guide the inleads 9 and 10 during assembly of a lamp into their proper positions at the vertices of the end walls 20, 21 and 22, 23 of the passage 8 and to hold them in such position after their outer ends are anchored in cavities 14 and 15, the portions thereof extending along the passage 8 will assume an angular position other than a parallel position with respect to the aforesaid vertices and with respect to each other. This would result in poor contacts or no contacts being made with the contacts of the lamp holder inserted in passage 8.

Such improper positioning of the inleads 9 and 10 is avoided in a positive manner, in accordance with the present invention, by the guide slot 24 defined by a molded integral part 25 of disk 5 at the inner end of the passage 8. The guide slot 24 (Figs. 2b and 3b) extends across the passage 8 between and terminates at the vertices of the end walls 20, 21 and 22, 23 (Figs. 2a and 3a) of the passage 8. The disk 5 is flared outwardly from the sides of the slot 24, as shown at 26, to facilitate threading the inleads 9 and 10 through the slot 24 and the passage 8 in assembling the base 3 on the lamp envelope 1.

The slot 24 is diamond-shaped at its center portion, and the length of its minoraxis, that is, the maximum width of the slot, is equal to the distance between the side walls 27 and 28 of the passage 8. The length of the slot 24 is equal to the distance between the vertices of the end walls 20, 21 and 22, 23 of the passage 8 and its major axis is in a plane including the cavities 14 and 15 and the longitudinal axis of the passage 8. The ends 29 and 30 of the slot are rounded and have short, parallel spaced sides merging with the sides of the diamond-shaped center portion thereof. The parallel sides at each end of the slot 24 are spaced apart a suflicient distance to receive an inlead wire therebetween and, when the inleads are anchored in the base as described below, the ends 29 and 30 of the guide slot offer additional support to the inleads at the vertices of the convergent walls 20, 21 and 22, 23.

In mounting the base 3 on the ends of the lamp envelope, the basing cement 6 is applied to the inner surface of the metal shell 4, theinleads 9 and 10 are threaded through the slot 24 and the passage 8. The base 3 is pressed onto the end of the envelope 1 to compress the basing cement 6 between the shell 4 and the envelope 1. After the cement 6 has been hardened to secure the base 3 to the envelope 1, the outer ends of the inleads 9 and 10 are moved laterally in opposite directions and bent over into the grooves 16 and 17 and the notches 18 and 19 in the face of the embossment 7.

The lateral movement of the part of the inleads in the passage 8 is guided by the sides of the slot 24 when the base 3 is in any rotational position on the envelopeand other than that shown in Fig. 2, so that the inleads move into the ends 29 and 30 of the slot 24. The portions of the inleads 9 and 10 in the passage 8 are thus guided into spaced parallel positions against the vertices of the convergent end walls 20, 21 and 22, 23 of the passage 8 for engagement with the holder contacts received in the passage 8 when mounting the based lamp in a holder.

After the outer portions of the inleads 9 and 10 have been so positioned in the grooves 16 and 17 and the notches 18 and 19, shown in Fig. 2, the parts thereof extending beyond the rounded ends of the embossment 7 are severed fiush with the said embossment ends. The parts of the inleads overlying the cavities 14 and 15 are then crimped into the said cavities to anchor the inleads 9 and 10 securely in the disk 5 of the base 3, asshown in Figs. 2, 4 and 5. This method of so anchoring the inleads in base 3 is disclosed and claimed in the Marz application referred to above.

The lamp shown in side elevation in Fig. 1 of the drawing may be about 8 feet in length and about 1% inches in diameter. The electrodes 11 sealed into the ends of the envelope 1 each comprises a tungsten-filament coated with electron-emissive material, such as alkaline-earth compounds, and each is of the type requiring preheating to an electron emitting temperature before starting of an electric discharge between the said electrodes at opposite ends of the lamp envelope. The envelope 1 contains a starting gas, such as argon, at a few millimeters pressure and a small measured quantity 31 of mercury, the vapor of which is at a pressure of about microns during operation of the lamp. A coating 32 of fluorescent material is provided on the inner surface of the envelope 1 and this material is excited to luminescence by the intense emission of 2537 A wave length radiation of the lowpressure mercury vapor discharge during operation of the lamp. Such lamps are commercially available and a species thereof is known in the trade as the rapid start fluorescent lamp.

The bases 2 and 3, in the manufacture of the lamp, are assembled at different times in such manufacture on the ends of envelope 1 and in their assembly with the lamp envelope the base assembled last is so positioned on its envelope end that the elongated embossments 7 on the bases 2 and 3 are coplanar, that is, each of the embossments 7 lies in the same plane including the longitudinal axis of the envelope 1. In accordance with the present invention, this plane may or may not include also the points at which the pairs of spaced inleads 9 and 10 emerge from the opposite ends of the envelope 1, the said points in such fluorescent lamps as presently manufactured being themselves coplanar in the sense that all of them lie in a common plane including the longitudinal axis of the tubular envelope 1.

What I claim as new and desire to secure by Letters Patent of the United States is:

l. A base for attachment to an end of an electric lamp having a pair of spaced wire inleads extending from said end, said base comprising an outwardly projecting electrically insulating body member provided with a passage for receiving both said spaced inleads, the outer face of said member having spaced apart recessed portions communicating with said passage for accommodating the end portions of inleads threaded through said passage, and an elongated guide slot extending across the inner end of said passage with the ends thereof aligned along said passage with the said outer recessed portions, the sides of said slot being convergent toward each of the ends thereof to. direct said wire inleads into spaced parallel positions in said passage and in line with said recesses during assembly of said base on said lamp, said recesses being greater in depth than the diameter of the inlead portions to be accommodated thereby to protect said inlead portions from accidental contacts.

2. A base for attachment to an end of a tubular envelope of a double-ended electric lamp having a pair of spaced wire inleads extending from each of its ends, said base comprising an outwardly projecting electrically insulating disk-shaped member provided with a central passage for receiving both said spaced inleads, the outer face of said member having recesses communicating with said passage for accommodating the end portions of said inleads threaded through said passage, said recesses being disposed in diametrically opposite positions with respect to said passage, and an elongated guide slot for said inleads at the inner end of said passage and extending across said passage with its ends in the plane including said recesses, the sides of said slot being convergent toward each of the ends thereof to direct said inleads into spaced parallel positions in said passage in line with said recesses during assembly of said base on said lamp, said recesses being greater in depth than the diameter of the inlead portions to be accommodated thereby to protect said inlead portions from accidental contacts.

3. A base for attachment to an end of a tubular envelope of a double-ended electric lamp having a pair of spaced wire inleads extending from each of its ends, said base comprising an outwardly projecting electrically insulatiug disk-shaped member provided with a central passage for receiving both said spaced inleads, said passage being of flattened cross section having vertices at its lateral ends, the outer face of said member having recesses communicating with said passage for accommodating the end portions of said inleads, said recesses being disposed in a plane including the vertices at the lateral ends of said flattened passage, and an elongated guide slot for said inleads at the inner longitudinal end of the passage, said slot extending across said passage with its ends in the plane including said vertices and said recesses, the center portion of said slot being diamond-shaped with its major axis included in said plane whereby the sides of said slot direct said inleads into spaced parallel positions in said passage in line with said recesses during assembly of said base on said lamp, said recesses being greater in depth than the diameter of the inlead portions to be accommodated thereby to protect said inlead portions from accidental contacts.

4. An electric lamp comprising an elongated tubular glass envelope having a pair of spaced inleads extending from each of its ends and a base attached to each end of said envelope, each of said bases comprising a member of insulating material having a central passage therethrough and recesses communicating with the outer end of said passage and extending in opposite directions therefrom across an exposed face of said member, said inleads extending from the end of said envelope into said passage and being anchored at their terminations in respective ones of said recesses, said member comprising also an inlead guide slot at the inner end of said passage, the sides of said slot being convergent toward the slot ends to direct the inleads into the ends of the slot during assembly of the lamp, the ends of said guide slot being coplanar with said recesses and the longitudinal axis of said passage to hold said inleads in parallel alignment with said passage, said recesses being greater in depth than the diameter of said inleads to protect said inleads from accidental contacts.

5. An electric lamp comprising an elongated tubular glass envelope having a pair of spaced inleads extending from each of its ends and a base attached to each end of said envelope, each of said bases comprising an electrically insulating disc-shaped member having a raised elongated embossment flattened in cross section and extending across its center and projecting outwardly from the base, said member having through the embossed portion thereof a hexagonal passage also slightly flattened in cross section and having vertices at its lateral ends, the outer face of said embossment having recesses communicating with said passage at the vertices of its lateral ends and extending in opposite directions across the outer face of said embossment, said inleads extending from the end of said envelope into said passage and being anchored at their terminations in respective ones of said recesses, said member comprising also an elongated guide slot for said inleads at the inner longitudinal end of the said passage, said guide slot extending across said passage with its ends at the vertices of the lateral ends of said passage, the center portion of said slot being diamond shape to direct the inleads into the ends of the slot during assembly of the lamp, the major axis of the center portion of the slot being included in the plane of said vertices and said recesses, the ends of said slot having parallel sides to hold said inleads in parallel alignment along the said vertices, the recesses in the outer face of said embossment being greater in depth than the diameter of said inleads to protect said inleads from accidental contacts.

References Cited in the file of this patent UNITED STATES PATENTS 

